The White House in December refused to accept the Environmental Protection Agency’s conclusion that greenhouse gases are pollutants that must be controlled, telling agency officials that an e-mail message containing the document would not be opened, senior E.P.A. officials said last week.

The document, which ended up in e-mail limbo, without official status, was the E.P.A.’s answer to a 2007 Supreme Court ruling that required it to determine whether greenhouse gases represent a danger to health or the environment, the officials said. This week, more than six months later, the E.P.A. is set to respond to that order by releasing a watered-down version of the original proposal that offers no conclusion. Instead, the document reviews the legal and economic issues presented by declaring greenhouse gases a pollutant.

Over the past five days, the officials said, the White House successfully put pressure on the E.P.A. to eliminate large sections of the original analysis that supported regulation, including a finding that tough regulation of motor vehicle emissions could produce $500 billion to $2 trillion in economic benefits over the next 32 years. The officials spoke on condition of anonymity because they were not authorized to discuss the matter.

Both documents, as prepared by the E.P.A., “showed that the Clean Air Act can work for certain sectors of the economy, to reduce greenhouse gases,” one of the senior E.P.A. officials said. “That’s not what the administration wants to show. They want to show that the Clean Air Act can’t work.”

The Bush administration’s climate-change policies have been evolving over the past two years. It now accepts the work of government scientists studying global warming, such as last week’s review forecasting more drenching rains, parching droughts and intense hurricanes as global temperatures warm.

But no administration decisions have supported the regulation of greenhouse gases under the Clean Air Act or other environmental laws. Tony Fratto, a White House spokesman, refused to comment on discussions between the White House and the Environmental Protection Agency. Asked about changes in the original report, Mr. Fratto said, “It’s the E.P.A. that determines what analysis it wants to make available” in its documents.

The new document, a road map laying out the issues involved in regulation, is to be signed by Stephen L. Johnson, the agency’s administrator, and published as early as Wednesday. The derailment of the original E.P.A. report was first made known in March by Representative Henry A. Waxman, Democrat of California, chairman of the House Oversight and Government Reform Committee. The refusal to open the e-mail has not been made public.

In early December, the E.P.A.’s draft finding that greenhouse gases endanger the environment used Energy Department data from 2007 to conclude that it would be cost effective to require the nation’s motor vehicle fleet to average 37.7 miles per gallon in 2018, according to government officials familiar with the document.

About 10 days after the finding was left unopened by officials at the Office of Management and Budget, Congress passed and President Bush signed a new energy bill mandating an increase in average fuel-economy standards to 35 miles per gallon by 2020. The day the law was signed, the E.P.A. administrator rejected the unanimous recommendation of his staff and denied California a waiver needed to regulate vehicle emissions of greenhouse gases in the state, saying the new law’s approach was preferable and climate change required global, not regional, solutions.

California’s regulations would have imposed tougher standards. The Transportation Department made its own fuel-economy proposals public almost two months ago; they were based on the assumption that gasoline would range from $2.26 per gallon in 2016 to $2.51 per gallon in 2030, and set a maximum average standard of 35 miles per gallon in 2020.

The White House, which did not oppose the Transportation Department proposals, has become more outspoken on the need for a comprehensive approach to greenhouse gases, specifically rejecting possible controls deriving from older environmental laws.

In a speech in April, Mr. Bush called for an end to the growth of greenhouse gases by 2025 — a timetable slower than many scientists say is required. His chairman of the Council of Environmental Quality, James Connaughton, said a “train wreck” would result if regulations to control greenhouse gases were authorized piecemeal under laws like the Clean Air Act and the Endangered Species Act.

White House pressure to ignore or edit the E.P.A.’s climate-change findings led to the resignation of one agency official earlier this month: Jason Burnett, the associate deputy administrator. Mr. Burnett, a political appointee with broad authority over climate-change regulations, said in an interview that he had resigned because “no more constructive work could be done” on the agency’s response to the Supreme Court.

He added, “The next administration will have to face what this one did not.” The House Select Committee for Energy Independence and Global Warming, led by Representative Edward J. Markey, Democrat of Massachusetts, has been seeking the discarded E.P.A. finding on the dangers of climate change.

After reading it last week, Mr. Markey’s office sent a letter to Mr. Bush saying, “E.P.A. Administrator Stephen Johnson determined that man-made global warming is unequivocal, the evidence is compelling and robust, and the administration must act to prevent harm rather than wait for harm to occur.”

Simultaneously, Mr. Waxman’s committee is weighing its response to the White House’s refusal to turn over subpoenaed documents relating to the E.P.A.’s handling of recent climate-change and air-pollution decisions. The White House, which has turned over other material to the committee, last week asserted a claim of executive privilege over the remaining documents.

In an interview on Sunday, Mr. Fratto, the White House spokesman, said the committee chairmen did not understand the legal precedent underlying executive privilege. “There is a long legal history supporting the principle that the president should have the candid advice of his advisers,” Mr. Fratto said.

(By FELICITY BARRINGER, NYT, 26/06/2008)